Screw propeller



G; H.- THOMPSON AND J. CURRIE. SCREW: PROPELLER.

APPLICATION HLED nEc.2a. 92o.

Patented June 6,1922.

ATTORNEY PATENT. omen.

GEORGE E. THOMPSON AND JOHN CURRIE, or SEATTLE, wAsHm K SCREW PROPELLESpecification of Letters Patent. Patent d J 19 Application filedDecember 28, 1920. Serial No. 433,572.

To all whom it may concern:

Be it known that we, GEORGE H. THOMP- SON, a subject of the King ofEngland and JOHN CURRIE, a citizen'of the United States,

residing at Seattle, in the county of King and State of Washington, haveinvented certain new and useful Improvements in Screw Propellers, ofwhich the following is a specification.

This invention for marine vessels.

The object of our invention is, generally,

to provide a device of this character'whereby power may be utilized morefully than hitherto for driving a vessel.

A specific object of the invention is to provide a propeller havingblades of large areas arranged to produce a minimum of drag and whichoperate with an absence of churning. p

The invention consists of a propeller having a plurality of bifurcatedblades of peculiar form which are disposed in spiral or helicalrelations. I

The invention further consists in the novel construction, adaptation andcombination of parts as will be hereinafter described and claimed.

In the accompanying drawings, Figure 1 is an end elevation of apropeller embodying our invention. Fig. 2 is a side elevation of thesame, and showing the relative arrangement of the blades. Figs. 3. 4,and

' 5 are sectional views through 3--3, 4-4,

and 5-5 of Fig. 1.

In said drawings, the numeral 10 designates thepropeller hub providedwith a plu-.

rality of bifurcated blades, denoted by A, B, C, which are disposedspirally about the hub for revolutions in different planes.

Each of said blades comprises a shank ele-' ment 11 and two flukeelements 12 and 13.

Said shank and flukes are formed to be approximately helical in sectionstaken concentric of the propeller axis. As shown in Fig. 4, the flukesare of substantially planoconvex forms in tranverse sections, the convexface being forward in the leading fluke and to the rear in the.following fluke of a blade. The leading fluke 12 is curved forwardlyfrom the shank to the tip thereof and the other fluke 13 is curvedrearwardly as best represented in Fig. 3, while the outer relates toscrew propellers.

with respect to the e whereby the water may travel in an unbroken statefrom in front of the leading fluke 12 to the rear of the following fluke'13.

Similar to the flukes, the blades themselves are-disposed in suchrelations with respect to each other to provide therebetween passagescircumferentially of the propeller.

By forming both the blades and the flukes thereof in helical relationsthey offer little resistance when revolving through the water butprovide a maximum driving force to propel a vessel.

The curving of the blades in the respective flukes from the region oftheir divergence to the fluke tips serves to reduce the centrifugalmovement of the water without breaking the same.

By arranging the blades and their flukes tions with respect to eachother about the hub, the bifurcation or fluke elements of said bladesbeing broad and of substantially plano-convex form in transverse sectionwith the convex sides of the complementary flukes at the'front-and rearsides respectively, the the complementary flukes of a blade being.curved to have the tipsv and outer side portions thereof respectivelydirected forwardly and rearwardly or toward each other and with 'theouter edges of each pair of flukes coextensive and in the similitude' ofan elongated letter S. Signed at Seattle, Washington, this 13t dayof'December 1920. H

GEORGE H. THOMPSON.

JOHN CURRIE. Witnesses: PIERRE BARNES, MARGARET G. SUPPLE.

of bifurcated blades disposed in helical rela-

